1. Field of the Invention
The present invention relates to devices used to expel or squeeze out contents out of collapsible tubes such as those used for toothpaste, cosmetics, liniments and any other types of pasty substances. Some of those devices also prevent the contents from flowing back into the tube and thus prevent waste and user aggravation.
2. Description of the Relevant Art
U.S. Pat. No. 5,782,385 by Soon , besides teaching its own patent, gives a comprehensive explanation for the recently found need for devices that help in expelling the contents of collapsible tubes. Said patent also reviews 3 design patents and 2 utility patents.
Given the rather simple nature of the device at hand, there is no need to elaborate in long sentences and paragraphs the specifics of each patent application, Soon's application did a terrific job of that. Suffice it to say that none of the prior art discussed offers the simple and convenient ability to quickly remove the device from an empty tube and putting it onto a new one.
For example, the device that Soon teaches states that a screw driver be used to separate the two portions of his tube squeezer and goes on to describe the 8 steps required to remove said tube squeezer from one tube before putting it onto another tube.
Besides the aforementioned prior art, U. S. Pat. No. 5,857,593 by Patronaggio, issued after Soon, is another variation of a device used for a similar purpose and so is U. S. Pat. No. 5,501,369 by Zeev.
Also of note is Canadian patent application number 2,127,113, by Naslund (which covers his original Swedish application number 441,261). The said patent is in a different classification and serves a different purpose but because it is similar in physical shape than the invention discussed in this application, some clarification need to be done:
It should be noted that Naslund goes into great lengths to describe his invention as being "particularly a bag clip" to close up bags and stop the contents from coming out whereas this present invention entitled "contents expeller for collapsible tube" is aimed at aiding contents to be expelled, not from bags but from tubes such as those used for paste, cream, ointments and such. Although at first glance the two inventions appear physically similar, they are taken from a different class and provide substantially different functions in substantially different ways.
That is why Naslund, in his Canadian patent 2,127,113 on page 3 lines 14-15 doesn't teach a pair of pressure plates but rather "an outwardly extending bridge 6 which is spaced from the bottom of the limb, so as to define a space 7." This part is designed to exert great force upon the bag in order to seal it and makes it harder for it to slide along the length of a bag.
It is important in Naslund that the said bridge be "elastically resilient" as per page 3, line 26. In other words, the bridge has to be compressed from its normal slightly convex shape into a flat or even concave shape in order to fully clamp and seal a bag. (see FIG. 5 of his said patent).
Since it is the object of this present invention to allow the content expeller to slide along the length of a collapsible tube in order to aid in expelling its content, much less pressure is required. Just enough for the content expeller to keep its place and not allow contents to flow backwards into the tube.
In view of the prior art cited above, it is believed that the present invention which will be described herein offers a much simpler and efficient way of performing the same useful duty as any of the other prior art.